I agree that a granularity of one minute isn't required - but programming
to the nearest quarter hour (like the old mechanical devices with
removeable pegs) would be nice.

Whilst I can see that hourly setting takes the other extreme, I am quite
willing to give up quarter hour granuality in exchange for the immediate
display of today's complete programme at all times. You can tell at a glance
whether the heating's going to turn off during the day and that the
programme looks sensible. I suspect many central heating programmers are set
to weird timings, but no-one ever notices.

But then, everyone has their own priorities.

Christian.